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Search Results: 1 - 10 of 10589 matches for " Andreas Wollstein "
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Dating the age of admixture via wavelet transform analysis of genome-wide data
Irina Pugach, Rostislav Matveyev, Andreas Wollstein, Manfred Kayser, Mark Stoneking
Genome Biology , 2011, DOI: 10.1186/gb-2011-12-2-r19
Abstract: An admixed population arises when individuals from two or more distinct populations start exchanging genetic material. Studying admixed populations can be particularly useful for understanding differences in disease prevalence and drug response among different populations. There is ample evidence that human populations have different susceptibility to diseases, exhibiting substantial variation in risk allele frequencies [1]. For example, genetic predisposition to asthma differs among the differentially-admixed Hispanic populations of the United States, with the highest prevalence observed in Puerto Ricans. Genetic variants responsible for the increased asthma prevalence in this population were localized using an admixture mapping approach [2]. This method allows the identification of disease causing variants by estimating ancestry along the genome, and narrowing the search to the genomic regions with ancestry from a population that has a greater risk for the disease [3,4]. The same approach was used to identify genetic loci that influence susceptibility to obesity, which is about 1.5-fold more prevalent in African-Americans than in European-Americans [5].Admixed populations are also of interest to population geneticists as they offer invaluable insights into the impact of various human migrations. For example, Polynesian populations are of dual Melanesian and Austronesian ancestry, with more maternal Austronesian and paternal Melanesian ancestry, highlighting the importance of sex-specific processes in human migrations [6]. The analysis of the pattern of sharing of chromosomal regions between populations has provided important insights into human colonization history including multiple migration waves into the Americas, and a complex movement of people across Europe [7]. A study of admixture patterns in Indian populations revealed that most Indians today trace their ancestry to two ancient, genetically-divergent populations [8].Analyses of admixture patterns in huma
GAGA: A New Algorithm for Genomic Inference of Geographic Ancestry Reveals Fine Level Population Substructure in Europeans
Oscar Lao ,Fan Liu,Andreas Wollstein,Manfred Kayser
PLOS Computational Biology , 2014, DOI: doi/10.1371/journal.pcbi.1003480
Abstract: Attempts to detect genetic population substructure in humans are troubled by the fact that the vast majority of the total amount of observed genetic variation is present within populations rather than between populations. Here we introduce a new algorithm for transforming a genetic distance matrix that reduces the within-population variation considerably. Extensive computer simulations revealed that the transformed matrix captured the genetic population differentiation better than the original one which was based on the T1 statistic. In an empirical genomic data set comprising 2,457 individuals from 23 different European subpopulations, the proportion of individuals that were determined as a genetic neighbour to another individual from the same sampling location increased from 25% with the original matrix to 52% with the transformed matrix. Similarly, the percentage of genetic variation explained between populations by means of Analysis of Molecular Variance (AMOVA) increased from 1.62% to 7.98%. Furthermore, the first two dimensions of a classical multidimensional scaling (MDS) using the transformed matrix explained 15% of the variance, compared to 0.7% obtained with the original matrix. Application of MDS with Mclust, SPA with Mclust, and GemTools algorithms to the same dataset also showed that the transformed matrix gave a better association of the genetic clusters with the sampling locations, and particularly so when it was used in the AMOVA framework with a genetic algorithm. Overall, the new matrix transformation introduced here substantially reduces the within population genetic differentiation, and can be broadly applied to methods such as AMOVA to enhance their sensitivity to reveal population substructure. We herewith provide a publically available (http://www.erasmusmc.nl/fmb/resources/GA?GA) model-free method for improved genetic population substructure detection that can be applied to human as well as any other species data in future studies relevant to evolutionary biology, behavioural ecology, medicine, and forensics.
Resenha de “Análise de Discurso Crítica” (Resende, V. M.; Ramalho, V. – S o Paulo: Contexto, 2006)
Maria Ester Wollstein Moritz
Linguagem em (Dis)curso , 2007,
Abstract:
Osteoarthritis of the Wrist STT Joint and Radiocarpal Joint
Ronit Wollstein,Julio Clavijo,Louis A. Gilula
Arthritis , 2012, DOI: 10.1155/2012/242159
Abstract: Our understanding of wrist osteoarthritis (OA) lags behind that of other joints, possibly due to the complexity of wrist biomechanics and the importance of ligamentous forces in the function of the wrist. Scaphotrapeziotrapezoidal (STT) OA is common, but its role in wrist clinical pathology and biomechanics is unclear. We identified the prevalence of radiographic STT joint OA in our hand clinic population and defined the relationship between STT and radiocarpal OA in wrist radiographs. One hundred consecutive wrist clinical and radiographic exams were retrospectively reviewed. Radiographs were evaluated for the presence and stage of OA. The mean age was 61.3 (±14.5) years. The radiographic occurrence of STT joint OA was 59% and of radiocarpal (RC) OA was 29%. Radiographic STT and RC joint OA were inversely related. Tenderness over the STT joint in physical exam was not associated with OA in the STT or other joints. STT OA in our series was not related to wrist pain. These findings support the discrepancy between radiographic and cadaver findings and clinically significant OA in this joint. The inverse relationship between STT and RC OA, as seen in scapholunate advanced collapse (SLAC) wrist, requires further biomechanical study.
Osteoarthritis of the Wrist STT Joint and Radiocarpal Joint
Ronit Wollstein,Julio Clavijo,Louis A. Gilula
Arthritis , 2012, DOI: 10.1155/2012/242159
Abstract: Our understanding of wrist osteoarthritis (OA) lags behind that of other joints, possibly due to the complexity of wrist biomechanics and the importance of ligamentous forces in the function of the wrist. Scaphotrapeziotrapezoidal (STT) OA is common, but its role in wrist clinical pathology and biomechanics is unclear. We identified the prevalence of radiographic STT joint OA in our hand clinic population and defined the relationship between STT and radiocarpal OA in wrist radiographs. One hundred consecutive wrist clinical and radiographic exams were retrospectively reviewed. Radiographs were evaluated for the presence and stage of OA. The mean age was 61.3 ( ± 14.5) years. The radiographic occurrence of STT joint OA was 59% and of radiocarpal (RC) OA was 29%. Radiographic STT and RC joint OA were inversely related. Tenderness over the STT joint in physical exam was not associated with OA in the STT or other joints. STT OA in our series was not related to wrist pain. These findings support the discrepancy between radiographic and cadaver findings and clinically significant OA in this joint. The inverse relationship between STT and RC OA, as seen in scapholunate advanced collapse (SLAC) wrist, requires further biomechanical study. 1. Introduction The role that the scaphotrapeziotrapezoidal (STT) joint plays in the biomechanics of the wrist joint and thumb is still uncertain. Therefore, the behaviour of this joint, when involved in osteoarthritis (OA), is understood even less. Furthermore, the magnitude of clinically significant (tender, painful) STT OA has not been established. OA in the STT joint is the second most common site of radiographic OA in the wrist, reported in 15–29% of wrist radiographs, yet a higher occurrence (up to 83.3%) has been documented in cadaver studies [1–3]. Since the prevalence of clinical STT joint arthritis is estimated in some studies to be about 11%; it is possible that radiographs underestimate the actual (cadaveric) occurrence of STT joint OA, and that furthermore, most cases of STT OA are not clinically significant and therefore remain undiagnosed [4]. Based on clinical observation, we hypothesize that the true incidence of STT joint OA is more common than the 15% described radiologically in the literature, and that radiographic OA in this joint is inversely related to the occurrence of radiographic OA in the radioscaphoid (RS) joint [3]. The specific aims of this study were to identify the prevalence of radiographic STT joint OA in the population seen in our hand clinic and to define the relationship between OA in the
Digital Quantification of Human Eye Color Highlights Genetic Association of Three New Loci
Fan Liu,Andreas Wollstein,Pirro G. Hysi,Georgina A. Ankra-Badu,Timothy D. Spector,Daniel Park,Gu Zhu,Mats Larsson,David L. Duffy,Grant W. Montgomery,David A. Mackey,Susan Walsh,Oscar Lao,Albert Hofman,Fernando Rivadeneira,Johannes R. Vingerling,André G. Uitterlinden,Nicholas G. Martin,Christopher J. Hammond,Manfred Kayser
PLOS Genetics , 2010, DOI: 10.1371/journal.pgen.1000934
Abstract: Previous studies have successfully identified genetic variants in several genes associated with human iris (eye) color; however, they all used simplified categorical trait information. Here, we quantified continuous eye color variation into hue and saturation values using high-resolution digital full-eye photographs and conducted a genome-wide association study on 5,951 Dutch Europeans from the Rotterdam Study. Three new regions, 1q42.3, 17q25.3, and 21q22.13, were highlighted meeting the criterion for genome-wide statistically significant association. The latter two loci were replicated in 2,261 individuals from the UK and in 1,282 from Australia. The LYST gene at 1q42.3 and the DSCR9 gene at 21q22.13 serve as promising functional candidates. A model for predicting quantitative eye colors explained over 50% of trait variance in the Rotterdam Study. Over all our data exemplify that fine phenotyping is a useful strategy for finding genes involved in human complex traits.
Concomitant presentation of carpal tunnel syndrome and trigger finger
Stephen A Rottgers, Davis Lewis, Ronit A Wollstein
Journal of Brachial Plexus and Peripheral Nerve Injury , 2009, DOI: 10.1186/1749-7221-4-13
Abstract: One-hundred and eight consecutive subjects presenting to our hand clinic with CTS and/or TF were evaluated. The existence of both of these conditions was documented through a standard history and physical examination. The definition of trigger finger was determined by tenderness over the A1 pulley, catching, clicking or locking. CTS was defined in the presence of at least two of the following: numbness and tingling in a median nerve distribution, motor and sensory nerve loss (median nerve), a positive Tinel's or Phalen's test and positive electrophysiologic studies.The average age of the participants was 62.2 ± 13.6 years. Sixty-seven patients presented with symptoms and signs of CTS (62%), 41 (38%) subjects with signs and symptoms of TF. Following further evaluation, 66 patients (61%) had evidence of concomitant CTS and TF. Fifty-seven patients (53% of all study patients) had diabetes. The rate of subjects with diabetes was similar among the groups (p = 0.8, Chi-square test).CTS and TF commonly occur together at presentation though the symptoms of one condition will be more prominent. Our results support a common local mechanism that may be unrelated to the presence of diabetes. We recommend evaluation for both conditions at the time of presentation.Trigger finger (TF) or stenosing tenosynovitis and carpal tunnel syndrome (CTS) together are in all probability the most common conditions treated by the hand surgeon. Previous studies have suggested a significant concurrence rate between these conditions, but the implications of this have not been fully explored [1-3].Some studies hypothesize that surgery for one entity will cause the other or that the carpal tunnel syndrome that is associated with the appearance of trigger digits is a separate entity [2,4]. We suggest these two conditions often coexist at presentation.The goal of this study was to quantify the co-existence of these two entities in patients at presentation and to compare this coexistence between patien
Ulnar sided wrist pain and distal radioulnar joint osteoarthritis; is surgical arthroplasty enough?
Ronit Wollstein,H. Kirk Watson,Jan Phillips,Julio Clavijo
Rheumatology Reports , 2012, DOI: 10.4081/rr.2012.e3
Abstract: Distal radioulnar joint (DRUJ) arthritis is a common cause of ulnar wrist pain in rheumatoid and osteoarthritis. Modified arthroplasty for the DRUJ is a minimally invasive procedure for the treatment of isolated DRUJ osteoarthritis. The purpose of this study was to evaluate the efficacy of the procedure and the incidence of related ulnar wrist pathology as well as the incidence of subsequent ulnar wrist surgeries. All patients having modified arthroplasty for the DRUJ between 1994-2008 were retrospectively reviewed. Measurements included range of motion, grip strength, and subjective status. Data regarding other wrist surgeries was recorded. There were 29 patients, 23 of which had a follow-up of over 8 weeks (average 16 months (SD=24). Fourteen patients had no to minimal pain, 6 had pain with heavier activities (2 severe), and 2 reported constant pain at the surgical site. Of the 4 more painful patients, three had additional surgery after the DRUJ arthroplasty. In all 96% of the patients had another procedure involving the ulnar- wrist complex either prior to surgery, at the time of surgery or following surgery for modified arthroplasty. We suggest that pathology involving the ulnar-wrist complex is often a syndrome consisting of multiple related diagnoses including but not limited to arthritis of the DRUJ. Multiple procedures may be needed, or a more aggressive approach such as ulnar head replacement may be indicated so that pathology at both the distal radioulnar and ulnocarpal joints is addressed concomitantly.
Economic Growth and a Low Carbon Economy―Does the Earth Suffer from an “Easter Island Syndrome”?  [PDF]
Andreas Oberheitmann
Low Carbon Economy (LCE) , 2011, DOI: 10.4236/lce.2011.24024
Abstract: The history of the Eastern Islands in the Pacific with an increasing over-utilization of natural resources reminds us of the mistakes modern societies are making and the question is obvious whether the Earth is suffering from an Eastern Islands Syndrome, in other words whether the egoism inherent in humans long-term might have fatal consequences for our species homo sapiens. Climate research identified two important phenomena, which should remind us of the Easter Islands: feedbacks and tipping points, i.e. self-accelerating phenomena of global warming and reaching irreversible points of climate change. Only a quick worldwide return to a low carbon economy is able to stabilize global warming on a bearable level. Both, Annex-I countries and Non-Annex-I countries have to contribute to reaching this goal taking their historical, current and future responsibilities into account. A post Kyoto regime based on cumulative per-capita CO2-emission rights and a international emission trading could provide for incentives to achieve a low carbon economy, especially for newly industrialized countries.
Development of a Low Carbon Economy in Wuxi City  [PDF]
Andreas Oberheitmann
American Journal of Climate Change (AJCC) , 2012, DOI: 10.4236/ajcc.2012.12007
Abstract: The development of a Low Carbon Economy is a vital instrument to encounter climate change and take into account the growing challenges of an increasing urbanization in China. Wuxi City in East China’s Jiangsu Province is starting to implement a Low Carbon City Plan for safeguarding a sustainable development of the city until 2020 and beyond. This paper aims at estimating the impact of the Low Carbon City plan for Wuxi’s energy demand and CO2-emissions until 2050. Using an econometric energy supply and demand model to estimate and forecast the Wuxi energy and CO2-balance aggregates until 2050, it compares a scenario without specific Low Carbon City measures to reduce sectoral CO2-intensities to a Low Carbon scenario implementing these measures according to the Low Carbon City Plan until 2020 and beyond. The decomposition of the Kaya-identity reveals that the increase of per capita income has the largest impact on the growth of CO2-emissions and the decrease of energy intensity of Gross Value Added the largest impact on the reduction of CO2-emissions in Wuxi. A decrease of population and CO2-intensity of Primary energy supply only have average contributions. The decrease of energy intensity of Gross Value Added is due to energy efficiency gains in the single economic sectors, but to a large extent due to structural changes of the economy away from energy intensive sectors such as iron and steel, chemical industry or cement industry towards the energy extensive service sectors. A growing residential sector also reduces the industrial share of energy demand. Only following the assumed national trend with a shift from CO2-intensive industries to a CO2-extensive service economy, the Low Carbon goal of a 50% reduction of CO2-intensity of Gross Value Added compared to 2005 cannot be reached in Wuxi. Specific sectoral CO2 -intensity goals have to be successfully observed by the economic sectors in Wuxi, especially by the industry. The promotion of combined heat and power generation also has to contribute to the specific activities in Wuxi.
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